Remove usage of COALESCE from dashboard chart

[bananatron]

• Fixes PG::SyntaxError: ERROR from timestamp #1305 which may actually be a non-issue.
• The verbosity may not be worth the advantage given the reproducibility of this issue.

[bensheldon]

This is lovely! Any chance you could try putting the entire COALESCE into Arel?

[bananatron]

@bensheldon I almost never use Arel so lmk if this is better/worse.

[bensheldon]

Sorry, I missed entirely that the Arel was then getting to_sql'ed into a larger block of text 🤦🏻

I'm still unsure of why those spaces got inserted into the SQL previously. I'll accept this and maybe someday it will be fully Arel-ized.

[bananatron]

@bensheldon I am also unsure :[ but my theory is some weird level rails dependency issue 🤷

[bananatron]

This is coming back with a bundler update, I wonder if the ruby version is somehow involved 🤔

ActiveRecord::StatementInvalid in GoodJob::Jobs#index This prevents me from viewing my jobs page.

Showing /Users/_/.rbenv/versions/3.3.1/lib/ruby/gems/3.3.0/gems/good_job-3.28.2/app/views/good_job/jobs/index.html.erb  where line #2 raised:

PG::SyntaxError: ERROR:  syntax error at or near ":"
LINE 1: ... ( good_jobs.scheduled_at ,good_jobs.created_at ) : : TIMEST...

Rails 7.1.3.2
Ruby 3.3.1
GoodJob 3.28.2
PG 15

This PR still seems to fix the issue fwiw.